Assume an object, O, imaged on the human retina and subsequently “seen” in the visual cortex of the brain. The quality of the image I, can be described in terms of how useful I is for “understanding” O and/or as the perceived similarity between O and I. Thus if one, or a combination, of the following items
a) the space (empty space, air, fluid) between the eye and the object is “contaminated” with fog, haze, smoke, snow, dust, silt or other types of dispersed particles (e.g. blood corpuscles)
b) the space (gas, fluid) between the eye and the object has a different wavelength dependent relative transparency compared to normal air or vacuum
c) the object O has limited colour content
d) the image is captured in conditions where retinal receptors have particularly limited capacity to separate luminance or colour differences, e.g. low-light conditions
occur, then the quality of the perceived image I can be severely disturbed which in turn means that the interpretation of I can be deficient. Such a disturbance in visual appearance can have grave practical consequences in situations like investigations of the body's interior (e.g. the eye), air traffic control, driving, other land or sea traffic, underwater work, fire fighting or other surveillance situations. Pathological details in the fundus of the eye can be missed because of blood contamination, an airplane or a ship can be missed in the fog, a fire fighter can lose his way in the smoke, a diver may not find his way out of a wreck. Thus, in such situations, the lack of effective image enhancing systems providing a possibility to facilitate the human interpretation of images, i.e. enhancing the human seeing, constitute a serious problem. Below some areas of interest and problems are discussed in more detail.
Aviation and Air Transport
Fog, smog, haze, snow, smoke, rain, clouds of living beings such as bugs and insects, e.g. grasshoppers, bees etc, low-light conditions, e.g. at dusk and dawn or inadequate lighting, i.e. inadequate for unaided detail perception, at airports and/or outside/inside cockpit, constitute a security risk for air travel in general and cause severe air traffic control problems with possible rerouting or cancellation of flights as a result Obviously, these problems may also cause negative economical consequences for both airline companies and passengers, and in the worst case even mortal accidents. Even though the air traffic is guided and controlled by sophisticated navigation and radar systems, there is still the need to have visual contact. Too many accidents have been caused by reduced visibility and unknown objects moving. Even a slight increase in visibility would give the pilot and air traffic controller a better chance to handle difficult situations. Thus, there is a need to provide means and methods that overcome or reduce these problems.
Land Transportation
In a similar way smog, haze, snow, smoke, rain, clouds of living beings such as bugs and insects, e.g. grasshoppers, bees etc, low-light conditions, e.g. at dusk and dawn or inadequate lighting, i.e. inadequate for unaided detail perception, constitute problems regarding road and railway safety and may also increase costs of goods transportation. Thus, there is a need to provide means and methods that overcome or reduce these problems.
Shipping
Even though ships usually have very sophisticated navigation equipment, e.g. radar, GPS and so forth, the crew still need to have visual contact with for instance shore line, small boats and other ships. It may be a problem to establish such a visual contact in environments containing smog, haze, snow, smoke, rain, clouds of living beings such as bugs and insects, e.g. grasshoppers, bees etc, low-light conditions, e.g. at dusk and dawn or inadequate lighting for unaided detail perception. As a consequence, either safety or shipping cost is compromised. Thus, there is a need to provide means and methods that overcome or reduce these problems.
Submarine Applications
Silt, particles, ‘floating’ sediments, wavelength filtering by water, inadequate lighting, i.e. inadequate for unaided detail perception under water, clouds of living beings such as e.g. algae, plankton etc all make human interpretation of images more difficult under water. A general problem is that all underwater work close to the bottom of the sea is difficult because of sea floor silt and how easily it is disturbed. This bottom disturbance creates a dense “fog” which highly reduces visibility. This is both a security problem and an economical problem during diving, or e.g. during installation work under water when using e.g. a submerged vehicle with video recording equipment. For instance, the diver may lose orientation with possible catastrophical consequences and some building and/or installation work become unnecessarily expensive or even impossible to carry out due to these problems. As an example, under-sea infrastructure such as bridges, dams, oil and gas pipelines, drilling platform parts, telecommunication cables, etc, must be constructed/installed, inspected and maintained, and all these activities require an accurate interpretation of underwater images in order to be carried out effectively. Also, ships and boats, commercial or for leisure purposes, must be maintained and inspected below the sea surface. If the boat is small this is done by lifting it out of the sea. If the ship is large it is done either by a diver or a video equipped ROV (Remotely Operated Vehicle) The processed video footage gives a much better picture of potential problems. A problem is that when the sea floor is accidentally disturbed, the silt will prevent any more work until it has set. This is both dangerous and leads to efficiency problems. Any underwater construction or inspection is difficult because of visibility problems, depending on the water quality, silt, and amount of particles and other of above visibility disturbances.
Thus, there is a need to find methods and means facilitating the human interpretation of images in such situations so as to, possibly in combination with video equipped “Remotely Operated Vehicles” (ROV), reduce the time and cost required for carrying out such activities and improving safety.
Medical Applications
Various particles, such as blood corpuscles, in medical recording or viewing situations (e.g. during opthalmology, eye fundus inspection, skin image inspection, identification of local cell variations in endoscopic images, etc.) make human interpretation of images more difficult which may lead to erroneous diagnoses and/or misjudgments regarding accurate medical treatment. Apart from causing human suffering, this causes economical problems in terms of costs for both society and patients, some of which may have to live with severe handicaps for the rest of their lives. Thus, there is a need to provide means and methods that overcome or reduce these problems.
Marine Archaeology
Marine archaeology means disturbing the bottom of the sea with great visibility problems. Often the only possibility to retrieve artefacts is through “vacuuming” and filtering, but that destroys a lot of information, for instance the position of the artefact. Thus, there is a need to provide means and methods that overcome or reduce these problems.
Land Archaeology
Finding the place for digs is much more efficient if it would be possible to utilize airplane mounted video equipment. However, a problem is that no effective image processing technology capable to find remains through difference in soil colour, for instance pole holes from houses and other constructions, is available today. Thus, there is a need to provide means and methods that overcome or reduce this problem.
Also, much of the age estimation in a dig is done through the knowledge of different soil layers dating from different time periods. There is thus a need to provide effective methods and means capable of facilitating the detection and interpretation of different soils providing a possibility to estimate the “historical age” of soils in an accurate and secure manner.
Agriculture
Polluted soil areas differ slightly in colour from the surroundings. The colour difference can be so small that it is difficult to detect it with pure visual inspection. Thus, there is a need to provide effective methods and means capable of facilitating the detection of polluted soil.
Crop quality and growth status can be seen in slight colour differences. The colour difference can be so small that it is difficult to detect it with pure visual inspection. There is a need to provide effective methods and means capable of detecting crop quality and growth status based on said colour differences in an accurate, secure and efficient way.
Food Safety
The quality degradation of food and eatables often manifests itself as small colour changes, for instance meat turns darker when it turns bad. There is a need to provide effective methods and means capable of detecting the quality degradation of food based on said colour changes in an accurate, secure and efficient way.
Energy Systems
In many cases airborne inspections are carried out for the purpose of power grid network planning, maintenance and control, e.g. in case of power failures, after storms, etc. Thus, there is a need to provide effective methods and means capable of facilitating the accurate interpretation of images captured during such airborne inspections, facilitating an effective planning, operation, maintenance and control of the power grid network.
Forestry
In many cases airborne inspections are used in forest maintenance and control, e.g. to investigate/estimate quality, growth, health status, environmental problems, illegal logging, etc. There is a need to provide effective methods and means capable of facilitating the accurate interpretation of images captured during such airborne inspections, allowing an effective inspection, maintenance and control of forests.
Monitoring/Security/Surveillance
Imagine a surveillance pan camera mounted immediately under the roof of an airport terminal building. The camera may be tilted and is mainly pointed at the tarmac. The camera is used for security surveillance as well as general activity surveillance. Imagine further that the weather conditions are foggy. In such situations it is certainly a problem that the detection of unauthorized personnel, which may be recognised e.g. by wearing clothes and/or objects having a specific form and/or reflection characteristics, is hindered by the low visibility. Thus, there is a need to provide effective methods and means capable of accurately distinguishing authorised personnel from unauthorised persons in colour images captured during difficult image conditions.
The information given in this background section is intended to better understand the invention and no information is admitted to be prior art with respect to the present invention by its mention in this background section.
Thus, there is a need to find methods and means that solves or alleviates the problems discussed above and which are capable of detecting various object representations in colour images in an effective and efficient way, e.g. for the applications discussed above.